US 2004O224.175A1 (19) United States (12) Patent Application Publication (10) Pub. No.: US 2004/0224.175 A1 HenderSOn (43) Pub. Date: Nov. 11, 2004

(54) MULTILAYERED FILM Publication Classification (76) Inventor: Kevin O. Henderson, Willoughby Hills, OH (US) (51) Int. Cl...... B32B 27/08 Correspondence Address: (52) U.S. Cl...... 428/515; 428/500 Heidi A. Boehlefeld Renner, Otto, Boisselle & Sklar, LLP Nineteenth Floor 1621 Euclid Avenue (57) ABSTRACT Cleveland, OH 44115-2191 (US) (21) Appl. No.: 10/835,041 This invention relates to a multilayer film for use as in-mold labels, comprising a core layer having an upper Surface and (22) Filed: Apr. 29, 2004 a lower Surface; a skin layer overlying the upper Surface of the core layer, a heat activatable layer bonded to the lower Related U.S. Application Data Surface of the core layer by a tie layer; wherein the core layer comprises a blend of a propylene homopolymer and at least (60) Provisional application No. 60/466,985, filed on May one polyterpene and wherein the multilayer film is oriented 1, 2003. in the machine direction only and heat Set.

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MULTILAYERED FILM 0009. In yet another aspect of the invention, the core layer blend of polypropylene homopolymer and polyterpene 0001. This application claims the benefit of provisional comprises about 50% to about 80% by weight of polypro patent application Serial No. 60/466,985 filed May 1, 2003, pylene homopolymer and about 20% to about 50% by and is hereby incorporated by reference in its entirety. weight of polyterpene, based on the weight of the polypro TECHNICAL FIELD pylene homopolymer and polyterpene. 0002 This invention relates to multilayered films and, more particularly, to multilayered films that are useful in BRIEF DESCRIPTION OF THE DRAWINGS making in-mold labels. Labels of this type are referred to as 0010 FIG. 1 is a schematic illustration of the side view “in-mold” labels because the labels are held in place within of a multilayered film embodying the present invention in a the mold that forms the container during the container particular form. forming process. 0011 FIG. 2 is a flow diagram illustrating a co-extrud BACKGROUND OF THE INVENTION ing, Stretching, and annealing line used to make the inven 0.003 Polymeric in-mold labels offer many aesthetic and tive multilayered film. functional advantages over paper labels in the labeling of 0012 FIG. 3 is a diagrammatic representation of a print containers made from polymeric resins using blow-molding, ing, cutting and Stacking line used in making the inventive injection molding or injection blow-molding. When a plastic in-mold labels. container such as a high density polyethylene (HDPE) Squeeze bottle is used to package a product Such as hair 0013 FIG. 4-7 diagrammatically illustrate the die cutting Shampoo, a package using a polymeric label is generally of the inventive in-mold labels to form stacks of labels. more appealing to consumers than a package using a paper 0014 FIG. 8 diagrammatically illustrates the use of the label. In many applications the use of polymeric in-mold Stacked labels in a molding operation. labels is required for reasons of appearance, handling, performance, moisture-resistance, conformability, durability DETAILED DESCRIPTION OF THE and compatibility with the container to be labeled. Poly INVENTION meric in-mold labels also enable clear or Substantially transparent labels with only the label indicia being visible to 0015 The term “overlies” and cognate terms such as the consumer. “overlying and the like, when referring to the relationship 0004 In-mold labeling procedures, however, are not of one or a first layer relative to another or a Second layer, without their own difficulties. For example, in-mold labeling refers to the fact that the first layer partially or completely is known to have problems with distortion of the label. lies over the second layer. The first layer overlying the Distortion is caused by using a construction material that is Second layer may or may not be in contact with the Second chemically different from the substrate. Distortion also can layer. For example, one or more additional layerS may be be caused by the pressure and the melting points of the positioned between the first layer and the Second layer. material. Another problem observed in in-mold labeling is 0016. The term “high density polyethylene" or “HDPE” blistering of the label. Blisters can be caused by trapped air refers to a polyethylene having a density of about 0.940 to or by insufficient initial adhesion to the container. about 0.965 g/cc. The term “LLDPE” or “linear low density polyethylene' refers to a polyethylene having a density of 0005. The in-mold label and labeling method of the present invention eliminates or reduces at least Some of about 0.850 to about 0.925 g/cc. these problems by initially adhering the label to the con 0017. The term “service temperature of the label” is the tainer, reducing distortion and blistering of the label. temperature of the label when used as an in-mold label while in the mold for making a polymeric container. The Service SUMMARY OF THE INVENTION temperature of the label may range from about 200 F (93.3 0006. This invention relates to a multilayer film for use in C.) to about 290°F (143.3° C), and in one embodiment making an in-mold label and to molded plastic articles about 200°F (93.3° C) to about 260°F (126.7° C), and in having an in-mold label as described herein. In one embodi one embodiment about 220 F. (104.4° C) to about 260° F. ment of the invention, the multilayer film comprises a core (126.7° C). layer having an upper Surface and a lower Surface; a skin 0018 Referring to FIG. 1, the inventive multilayered layer overlying the upper Surface of the core layer; a heat film, in one of its illustrated embodiments, is generally activatable layer bonded to the lower Surface of the core indicated by the reference numeral 100, and is comprised of: layer by a tie layer; wherein the core layer comprises a blend a core layer 110 which has a first surface 112 and a second of a propylene homopolymer and at least one polyterpene surface 114; and skin layer 120 overlying the first surface and wherein the multilayer film is oriented in the machine 112 of the core layer 110, a heat activatable layer 130 direction only and heat Set. overlying the Second Surface 114 of the core layer, and a tie 0007. In one aspect of the invention, the polypropylene layer 140 positioned between the second surface 114 of the homopolymer of the core layer comprises a nucleated core layer 110 and the heat activatable layer 130. polypropylene homopolymer having a melt flow rate of at 0019. The overall thickness of the multilayered film 100 least 8 g/10 min. may be in the range of about 2.5 to about 8 mils, and in one 0008. In another aspect of the invention, the thickness of embodiment about 2.5 to about 4.5 mils, and in one embodi the heat activatable layer is about 20% of the overall ment about 3 to about 4.5 mils. The thickness of the core thickness of the multilayer film. layer 110 may range from about 40% to about 80% of the US 2004/0224175 A1 Nov. 11, 2004

overall thickness of the multilayered film 100, and in one terpene resin. In one embodiment, the blend comprises about embodiment about 45% to about 65%, and in one embodi 50% to about 60% by weight of polypropylene resin and ment about 55% of the overall thickness of the film 110. The about 40% to about 50% of polyterpene resin. skin layer 120 may have a thickness of about 1 to about 25% 0025. In addition to the high melt flow polypropylene of the overall thickness of the film 100, and in one embodi resin and the polyterpene resin, the core layer may also ment 5 to about 20%, and in one embodiment about 15% of contain other film forming polymeric resins in a lesser the overall thickness of the film 100. The heat activatable amount, generally about 0 to 20% by weight based on the layer 130 may have a thickness equal to about 5 to 30% of total weight of the core layer. In one embodiment, the core the overall thickness of the film 100, and in one embodiment layer contains about 0 to 15% by weight, and in another about 10 to 25%, and in one embodiment about 20% of the embodiment, about 4.5% by weight based on the total overall thickness of the film 100. Tie layer 140 may have a weight of the core layer. Such polymeric resins include high thickness equal to about 3 to about 15% of the overall density polyethylene, a copolymer of ethylene and propy thickness of the film 110, and in one embodiment about 7 to lene, a polystyrene, a polyamide, a polyester, a polyester about 12%, and in one embodiment about 10% of the overall copolymer, a polycarbonate, a cyclic olefin copolymer, a thickness of the film 100. cyclic olefin copolymer, or a mixture of two or more thereof. 0020 Core Layer 0026. In one embodiment, the core layer of the multilayer 0021. The core layer 110 may be comprised of a polypro film comprises a medium impact copolymer polypropylene pylene resin having a high melt flow rate and a polyterpene in addition to the high melt flow polypropylene resin and resin. AS used herein, the term “high melt flow rate” means polyterpene resin blend. The medium impact copolymer that the melt flow rate is at least 8 g/10 min. In one generally are made by incorporating a rubbery material, embodiment, the polypropylene resin comprises a polypro ethylene-propylene rubber in the reactor with polypropy pylene homopolymer. An example of a commercially avail lene. The ethylene-propylene rubber is an elastomer, made able nucleated polypropylene homopolymer that may be by the copolymerization of ethylene and propylene and used is P4C5K-123A from Huntsman. This material is typically contains 25% to 90% ethylene. Commercially identified as having a melt flow rate of 20 g/10 min. (ASTM available medium impact copolymers include Escorene D1238), a density of 0.90 g/cm (ASTM D1505) and a PP7032, having a melt index of 4.5 g/10 min and a density flexural modulus of 1680 MPa (ASTM D790). Another of 0.90 g/cc, Escorene PP7033, having a melt index of 8 g/10 example of a commercially available polypropylene min and a density of 0.90 g/cc, and Escorene PD7623. E1 homopolymer that may be used is Marlex(RHGN-200 from having a melt index of 7 g/10 min from ExxonMobil. Chevron Phillips Chemical Co. This material is identified as a nucleated polypropylene homopolymer having a melt flow 0027 Various nucleating agents and pigments can be incorporated into the film core formulations of the present rate of 20 g/10 min. (ASTM D1238), a density of 0.907 invention. The amount of nucleating agent added should be g/cm (ASTM D1505) and a flexural modulus of 1999 MPa an amount Sufficient to provide the desired modification of (ASTM D790). the crystal Structure while not having an adverse effect on 0022. The polyterpene resin blended with the polypro the desired properties of the film. It is generally desired to pylene resin provides improved Stiffening action, increased utilize a nucleating agent to modify the crystal Structure and modulus and increased Strength of the resulting film. The provide a large number of considerably Smaller crystals or polyterpene resins are a well-known class of resinous mate spherulites to improve the transparency (clarity), and stiff rials obtained by the polymerization or copolymerization of neSS, and the die-cuttability of the film. Nucleating agents terpene hydrocarbons Such as the alicyclic, mono-cyclic and that have been used for polymer films include mineral bicyclic terpenes, and their mixtures, including carene, nucleating agents and organic nucleating agents. Examples isomerised pinene, dipentene, terpinene, terpinolene, turpen of mineral nucleating agents include carbon black, Silica, tine, a terpene cut or fraction, and various other terpenes. kaolin and talc. Among the organic nucleating agents that 0023 The hydrogenated polyterpenes are also effective have been used in polyolefin films include Salts of aliphatic for improving the properties of the films. These are produced mono-basic or di-basic acids or arylalkyl acids Such as by hydrogenating the polyterpenes by any of the usual Sodium Succinate, Sodium glutarate, Sodium caproate, hydrogenation processes. Generally the hydrogenation is Sodium 4-methylvalerate, aluminum phenyl acetate, and Sodium cinnamate. Alkali metal and aluminum Salts of carries out utilizing a catalyst Such as nickel, nickel on aromatic and alicyclic carboxylic acids Such as aluminum kieSelguhr, copper chromite, palladium on alumina, or benzoate, Sodium or potassium benzoate, Sodium beta-naph cobalt plus Zirconia or kieselguhr. The hydrogenation is tholate, lithium benzoate and aluminum tertiary-butylben preferably carried out in the presence of a Solvent Such as Zoate also are useful organic nucleating agents. Substituted methyl cyclohexane, toluene, p-methane, etc., utilizing pres sorbitol derivatives such as bis(benzylidene) and bis(alkyl Sures ranging from 500 to 10,000 psi and a temperature of benzilidine) Sorbitols wherein the alkyl groups contain from 150 to 300° C. Useful hydrogenated polyterpenes include about 2 to about 18 carbon atoms are useful nucleating those having a melt index of 8-15 g/10 min. at 190° C. An agents. More particularly, Sorbitol derivatives Such as 1,3, example of a commercially available hygrogenated polyter 2,4-dibenzylidene Sorbitol, 1,3,2,4-di-para-methylben pene resin is Exxelor PA 609A from ExxonMobil. This resin Zylidine Sorbitol, and 1,3,2,4-di-para-methylbenzylidene Sor is identified as having a melt index of 11 g/10 min. (ASTM bitol are effective nucleating agents for polypropylenes. D 1238) and a density of 0.975 g/cm (ASTM D1505). Useful nucleating agents are commercially available from a 0024. The blend of polypropylene resin and polyterpene number of sources. Millad 8C-41-10, Millad 3988 and resin is comprised of about 50% to about 80% by weight of Millad 3905 are sorbitol nucleating agents from Milliken polypropylene resin and about 20% to about 50% of poly Chemical Co. US 2004/0224175 A1 Nov. 11, 2004

0028. A particularly useful nucleating agent is a complex about 8 carbon atoms, and in one embodiment 1 to about 2 organophisphite compound commercially available under carbon atoms. The functional monomer(s) component of the the trade name ADK Stabilizer NA-21 from Amfine Chemi copolymer or terpolymer may range from about 1 to about cal Corporation. This compound is identified as aluminum, 15 mole percent, and in one embodiment about 1 to about 10 hydroxybis 2,48,10-tetrakis (1,1-dimethylethyl)-6-hy mole percent of the copolymer or terpolymer molecule. droxy-12H-dibenzod.g1,3,2-dioxaphoshocin 6-oxidato). Examples include: ethylene/vinyl acetate copolymers, eth ylene/methyl acrylate copolymers, ethylene/ethylacrylate 0029. The core layer 110 may include one or more copolymers, ethylene/butyl acrylate copolymers, ethylene/ pigments. The pigments that may be used include titanium methacrylic acid copolymers, ethylene/acrylic acid copoly dioxide. In one embodiment, a concentrate containing the mers, ethylene/methacrylic acid copolymers containing pigment and a resin carrier is added to the mixture used to Sodium or Zinc (also referred to as ionomers); acid-, anhy extrude the core layer. The concentrate may contain about dride- or acrylate-modified ethylene/vinyl acetate copoly 20% to about 80% by weight pigment, and about 80% to mers, acid-or anhydride-modified ethylene/acrylate copoly about 20% by weight resin carrier. The resin carrier may be mers, anhydride-modified low density polyethylenes, any thermoplastic polymer having a melting point or glass anhydride-modified linear low density polyethylene, and transition temperature in the range of about 90° F (32.2°C.) mixtures of two or more thereof. In one embodiment, to about 250 F. (121.1° C). Examples include polyethyl ethylene/vinyl acetate copolymers that are particularly use ene, polypropylene, polystyrene, rubber modified polySty ful include those with a vinyl acetate content of at least about rene, ABS, polymethyl methacrylate, polycarbonate, and the 10% by weight, and in one embodiment about 18% to about like. In one embodiment, a titanium dioxide concentrate is 25% by weight. Examples of commercially available used which is comprised of a blend of about 20% to about copolymers and terpolymers that can be used include the 50% by weight linear low density polyethylene and about ethylene/vinyl acetate copolymers available from AT Plas 50% to about 80% by weight titanium dioxide. An example tics under the tradename EVA 1821. These copolymers and of a commercially available pigment concentrate that may terpolymerS may be present in the skin layer 120 at con be used is available from Ampacet Corp. under the trade name Ampacet 110069. Another example of a commercially centrations of up to about 50% by weight, and in one available pigment concentrate that can be used is available embodiment about 10 to about 35% by weight, and in one from A. Schulman Inc. under the tradename Polybatch embodiment about 50% by weight. P8555-SD, which is identified as a white color concentrate 0035) The skin layer 120 may be further comprised of an having a titanium dioxide concentration of 50% by weight in additional thermoplastic polymeric material. This polymeric a polypropylene homopolymer carrier resin. The concentra material may be a high density polyethylene, polystyrene, tion of pigment in the core layer 110 may be up to about 30% rubber modified polystyrene, acrylonitrile butadiene Styrene by weight based on the weight of the core layer, and in any (ABS), polypropylene, polyvinylidene fluoride, polyester, embodiment in the range of about 1% to about 20% by cylic olefin copolymer, and mixtures of two or more thereof. weight, and in one embodiment about 1 to about 15% by An example of a commercially available material is Equistar weight. H6012 which is identified as a high density polyethylene. In one embodiment, the polymeric material comprises a poly 0.030. In one embodiment, the core layer comprises about terpene resin. Such polyterpene resins are described above 45% to about 70% by weight of polypropylene homopoly with reference to the core layer. The polymeric material may mer, about 15% to about 40% by weight of polyterpene be present in layer 120 at a concentration of about 25 to resin, about 5% to about 15% by weight of pigment, and about 100 percent by weight, and in one embodiment about about 2% to about 15% by weight of a low density poly 60 to about 95 percent by weight. ethylene, based on the total weight of the core layer. 0036). In one embodiment, the skin layer 120 comprises a 0031. In one embodiment, the core layer comprises about blend of a polypropylene homopolymer and a filler material. 45% by weight of nucleated polypropylene homopolymer, The polypropylene homopolymers useful for the Skin layer about 40% by weight polyterpene resin, about 10.5% tita are those described above with reference to the core layer. nium dioxide, and about 4.5% of a low density polyethylene, Particularly useful in the skin layer are nucleated polypro based on the total weight of the core layer. pylene homopolymers. The fillers that can be used include calcium carbonate and talc. In one embodiment, the filler is 0032. In another embodiment, the core layer comprises added to the skin layer material in the form of a concentrate about 45% by weight of nucleated polypropylene homopoly containing the filler and a resin carrier. The concentrate may mer, about 40% by weight polyterpene resin, and about 15% contain, for example, about 20% to about 80% by weight of a low density polyethylene, based on the total weight of filler, and about 20% to about 80% by weight resin carrier. the core layer. The resin carrier can be any thermoplastic polymer having a melting point in the range of about 100° C. to about 265 0033 Skin Layer C. Examples include polyethylene, polypropylene, polybu 0034. In one embodiment, skin layer 120 may be com tylene, polyester, nylon, and the like. Also included are prised of a thermoplastic copolymer or terpolymer derived thermoplastic copolymerS Such as ethylene methylacrylate, from ethylene or propylene and a functional monomer and the like. In one embodiment, a calcium carbonate Selected from alkyl acrylate, acrylic acid, alkyl acrylic acid, concentrate is used that is comprised of a blend of about Vinyl acetate and combinations of two or more thereof. In 50% to about 80% by weight polypropylene and about 20% one embodiment, the functional monomer is Selected from to about 50% by weight calcium carbonate. An example of alkyl acrylate, acrylic acid, alkyl acrylic acid, and combi a commercially available filler concentrate that can be used nations of two or more thereof. The alkyl groups in the alkyl is available from A. Schulman Inc. under the tradename PF acrylates and the alkyl acrylic acids typically contain 1 to 920, which is identified as a calcium carbonate concentrate US 2004/0224175 A1 Nov. 11, 2004 having a calcium carbonate concentration of 40% by weight 0042. In one embodiment, the tie layer comprises a blend in a polypropylene homopolymer carrier resin. Another of a propylene homopolymer and a low density polyethyl example is Ampacet 101087 which is a product of Ampacet ene. The low density polyethylene may comprise a metal Corporation identified as a calcium carbonate concentrate locene catalyzed linear low density polyethylene as containing 70% by weight calcium carbonate and 30% by described above with reference to the skin layer. The tie weight ethylene methylacrylate. The concentration of filler layer may comprise about 55% to about 80% by weight of in the skin layer 120 can be up to about 40% by weight, and a propylene homopolymer and about 20% to about 45% by when used is generally in the range of about 10% to about weight of a low density polyethylene, based on the total 40% by weight, and in one embodiment about 10% to about weight of the tie layer. In one embodiment, the low density 35% by weight. polyethylene has a melt index (MI) of greater than 2 g/10 0037 Skin layer 120 may also be comprised of a poly min., and in one embodiment an Ml of greater than 5 g/10 ethylene having a density of 0.940g/cm or less. Such . polyethylenes generally are referred to in the art as low 0043 Heat Activatable Layer density or medium density polyethylenes, and these poly ethylene homopolymers can be prepared by techniques well 0044) The heat activatable layer 130 is a layer of material known to those skilled in the art including high pressure, that is activated by heat during the molding process to free radical catalyzed processes and processes using metal improve the bonding of the label to a plastic article in the locene catalysts. Low density polyethylenes and metal molding process. Material for the heat-activatable layer may locene catalyzed processes for preparing Such polyethylenes comprise a thermoplastic film material. Such materials are described in U.S. Pat. Nos. 5,358,792; 5,462.809; 5,468, include, but are not limited, to the film-forming materials 440; 5,475,075; and 5,530,054. Each of these patent is used alone or in combination Such as polyolefin, (linear or hereby incorporated by reference for its disclosure of met branched), metallocene catalyzed polyolefins, Syndiotactic allocene catalysts, polyethylenes, and methods for preparing polystyrenes, Syndiotactic polypropylenes, cyclic polyole polyethylenes. Metallocene-catalyzed polyethylenes gener fins, polyacrylates, polyethylene ethyl acrylate, polyethyl ally have a density of from about 0.850 to about 0.925 ene methyl acrylate, acrylonitrile butadiene Styrene polymer, g/cm, and more often from about 0.860 to about 0.920 ethylene-Vinyl alcohol copolymer, ethylene-Vinyl acetate g/cm. Examples of commercially available metallocene copolymers, polyamides Such as nylon, polystyrenes, poly catalyzed LLDPE include Exact 4151, Exact 0210, Exact urethanes, polysulfones, polyvinylidine chlorides, polycar 0230, Exact 8203 and Exact 8210 from ExxonMobil and bonates, Styrene maleic anhydride polymers, Styrene acry Dow Affinity PT 1450 and Affinity 8185 from Dow Chemi lonitrile polymers, monomers based on Sodium or Zinc Salts cal Company. or ethylene/methacrylate acid, ethylene methyl acrylate, ethylene acrylic acid and ethylene ethyl acrylate. Also 0.038. In one embodiment, the skin layer 120 comprises included are polymers and copolymers of olefin monomers about 45% to about 75% by weight of a polypropylene having, for example, 2 to about 12 carbon atoms, and in one homopolymer, about 5% to about 35% by weight of a filler embodiment 2 to about 8 carbon atoms. These include the material Such as calcium carbonate, and about 5% to about polymers of C-olefins from 2 to about 4 carbon atoms per 45% by weight of a low density polyethylene, based on the molecule. These include polyethylene, polypropylene, poly total weight of the skin layer. The polypropylene homopoly mer may comprise a nucleated polypropylene homopolymer 1-butene, etc. having a melt flow rate of at least 8 g/10 min., and in one 0045. In one embodiment, the heat activatable layer com embodiment, at least about 10 g/10 min, and in one embodi prises a low density polyethylene. Such low density poly ment, about 20 g/10 min. ethylenes are described above with reference to the skin layer 120. Particularly useful low density polyethylene 0039) Skin layer 120 may be surface treated to enhance resins include plastomers that are any of a number of the printability of the Surface. For example, the outer Surface ethylene, C.-olefin copolymers. This ethylene copolymer has of skin layer 120 may be exposed to an electron discharge a density in the range of from 0.850 to 0.925 g/cc, or from treatment, e.g., corona treatment. Other Surface treatments to 0.860 to 0.910 g/cc or from 0.880 to 0.910 g/cc. The C-olefin enhance the printability of the skin layer are well known. used to make the ethylene C-olefin copolymer is Selected 0040 Tie Layer from one or more of propylene, butene-1, 4-methyl-1- pentene, pentene-1, hexene-1, octene-1, decene-1 and mix 0041. The multilayer film of the present invention at least tures thereof. Such combinations include, but are not limited one tie layer 140 positioned between the core layer and the to, copolymerS Such as ethylene/propylene; ethylene/butene heat activatable layer. The tie layer may comprise any 1; ethylene/hexene-1, ethylene/pentene-1, ethylene/4-me polymeric material that improves the adhesion of the heat thyl-1-pentene, ethyene/octene-1, ethylene/propylene/ activatable layer to the core layer. The film forming ther butene-1, ethylene/propylene/hexene-1, ethylene/propylene/ moplastic polymeric materials that can be used include pentene-1, ethylene/propylene/octene-1, and the like. polypropylene, copolymers of ethylene and propylene, Examples of commercially available plastomers include medium density polyethylene (density of about 0.924 to Exact 4151, Exact 0210, Exact 0230, Exact 8210 and Exact about 0.939 g/cc), terpolymers of ethylene, vinyl acetate and 8203 from ExxonMobil and Affinity PT 1450 and Affinity maleic anhydride, and terpolymers of ethylene, Vinyl acetate 8185 from Dow Chemical Company. and acrylic acid. In one embodiment, the tie layer comprises a medium impact copolymer polypropylene. An example of 0046) Also, the heat activatable layer may contain anti a commercially available medium impact copolymer that block additives Such as Silica, diatomaceous earth, Synthetic may be used is Escorene PD7623. E1 from ExxonMobil, Silica, glass spheres and ceramic particles. Polymeric par identified as having a melt index of 7 g/10 min. ticles Such as polymethyl methacrylate fine particles, US 2004/0224175 A1 Nov. 11, 2004

crosslinked polymethyl methacrylate fine particles, is sometimes referred to as the “machine direction.” The crosslinked polystyrene fine particles, Silicone resin fine term “cross direction' is used herein to refer to the direction particles and polytetrafluoroethylene fine particles may be going across the film at an angle of 90 from the machine used as the antiblock additive. A particularly useful anti direction. block additive comprises polymeric particles having a par ticle size of about 5 microns in a resin carrier. The resin 0050. During the hot-stretching step, the film is stretched carrier may comprise a low density polyethylene. A com and this stretching causes voids to form adjacent to or mercially available antiblock additive useful in the present around the particulate solids. The solids act as “seeds” for invention is Seablock-4, also referred to as Ampacet 400880 the Voids. The degree of Stretching is controlled to provide from Ampacet Corporation. The amount of antiblock addi the density reduction of about 5% to about 25%, as indicated tive that is used may be varied for particular formulations above. While not wishing to be bound by theory, it is and processing conditions. In one embodiment, the amount believed that this controlled stretching and void formation that is used may range up to about 0.5% by weight, and in followed by the above-indicated annealing Step is respon one embodiment, from about 0.01% to about 0.35%, and in sible for the relatively smooth print Surfaces that are one embodiment about 0.3% by weight. achieved with the inventive labels. 0051. The inventive multilayered film may be co-ex 0047 The heat activatable layer may also contain a slip truded, hot-stretched and annealed using the processing line agent. The Slip agents that are particularly useful include depicted in FIG. 2. The processing line depicted in FIG. 2 non-migratory Slip agents. A commercially available non will be described with reference to the film 100 illustrated in migratory Slip agent is Ampacet 101501 from Ampacet FIG.1. The processing line includes extruders 200,210, 220 Corporation, identified as a concentrate containing 10% by and 230, feed block 240 and die 250. Extruder 200 is used weight of a slip agent dispersed in a low density polyeth for extruding heat activatable layer 130. Extruder 210 is ylene. The amount of Slip agent that is used may be varied used for extruding tie layer 140. Extruder 220 is used for for particular formulations and processing conditions. In one extruding core layer 110. Extruder 230 is used for extruding embodiment, the amount that is used may range up to about skin layer 120. The extrudate from the extruder 200 is 1.5% by weight, and in one embodiment, from about 0.01% advanced to the feedblock 240 while at a temperature in the to about 1.2%, and in one embodiment about 1.0% by range of about 390° F (198.9° C) to about 470° F (243.3° weight. C.), and in one embodiment about 400° F (204.4° C.). The extrudate from the extruder 200 is advanced to the feed 0048. The heat activatable layer may also contain an block 240 while at a temperature in the range of about 400 antistatic additive. These additive as used to dissipate Static F. (204.4° C) to about 470° F (243.3° C), and in one electricity charges. The antistatic additives that are particu embodiment about 430° F (221.1° C). The extrudate from larly useful include non-migratory antistats. Charge dissi the extruder 200 is advanced to the feed block 240 while at pation for Such non-migratory anitStats is not dependent on a temperature in the range of about 390° F (198.9° C) to humidity for functionality. Rather charge dissipation occurs about 470° F (243.3° C), and in one embodiment about by an electron tunneling mechanism. Commercially avail 400° F (204.4° C.). The extrudate from the extruder 200 is able non-migratory antistatic additives include Ampacet advanced to the feedblock 240 while at a temperature in the 101710 from Ampacet Corporation, identified as a concen range of about 390° F (198.9° C) to about 470° F (243.3° trate containing 50% by weight of an antistatic additive C.), and in one embodiment about 400° F (204.4° C.). The dispersed in a low density polyethylene. The amount of extrudates from each of the extruders 200,210, 220 and 230 antistatic additive that is used may be varied for particular are combined in feedblock 240 and extruded through die 250 formulations and processing conditions. In one embodiment, to form film extrudate 255. Feedblock 240 and die 250 are the amount that is used may range up to about 10% by operated at a temperature in the range of about 400 F. weight (active ingredient), and in one embodiment, from (204.4° C) to about 470° F (243.3° C), and in one embodi ment about 435° F (223.9° C.). The film extrudate 255 about 0.01% to about 15%, and in one embodiment about extruded from die 250 may have a film thickness of about 10 5.0% by weight based on the total weight of the heat to about 20 mils, and in one embodiment about 12 to about activatable layer. 15 mils. Air knife 260 is used to adhere film extrudate 255 0049. The hot-stretching and annealing steps used in to cast roll 270. The film extrudate 255 is advanced from cast making the inventive film enhance the physical properties of roll 270 to cast roll 280, over cast roll 280, between cast roll the film. Hot-Stretching is performed at a temperature above 280 and cast nip roll 290, and then over guide rolls 300,320, the expected Service temperature of the label and provides 330, 340 and 350 to machine direction orientation unit 360. the film with a machine direction orientation. The density of Cast roll 270 is operated at a temperature of about 135 F. (57.2° C) to about 185° F (85° C), and in one embodiment the film is reduced during this step by about 5% to about about 160° F (71.1° C). Cast roll 280 is operated a 25%, and in one embodiment about 15% to about 20%. The temperature of about 100° F (37.8° C) to about 150° F. film is annealed at a temperature above the expected Service (65.6°C.), and in one embodiment about 120° F (48.9° C). temperature of the label to reduce Shrinking, relaxing or The film is advanced over cast rolls 270 and 280 at a rate of distortion of the film which may interfere with the in-mold about 40 to about 110 feet per minute, and in one embodi labeling process. During the hot-Stretching and annealing ment about 85 feet per minute. The thickness of the film 255 Steps, the extrudate is advanced through a Series of relatively is monitored using film thickneSS measuring device 310 as hot and cool rolls which contact the extrudate and impart the film advances from guide roll 300 to guide roll 320. In heat to the extrudate or remove heat from it under time the machine direction orientation unit 360, the film advances temperature-direction conditions established by line Speed, from pre-heat roll 370 to pre-heat roll 380. Pre-heat roll 370 temperature, roll size, and Side of contact. The direction at is operated at a temperature of about 130 F. (54.4° C.) to which the film advances through the rolls is the direction at about 170° F (76.7° C), and in one embodiment about 150 which the film is hot-stretched and is oriented. This direction F. (65.6° C). The film is advanced over pre-heat roll 370 at US 2004/0224175 A1 Nov. 11, 2004

a rate of about 40 to about 110 feet per minute, and in one energy on the Surface of the skin layer 120 is increased embodiment at about 86 feet per minute. Pre-heat roll 380 is Sufficiently to enhance adhesion of ink to the Surface during operated at a temperature of about 145 F. (62.8°C.) to about Subsequent printing operations. The film is advanced from 185° F (85° C), and in one embodiment about 165° F. the corona treating station 540 through nip rolls 550 to (73.9° C). The film advances over pre-heat roll 380 at a rate cooling nip roll 560, between cooling nip roll 560 and of about 40 to about 120 feet per minute, and in one cooling roll 570, over cooling roll 570 to roll 580 where it embodiment about 89 feet per minute. The film is advanced is wound on the roll for Subsequent processing. The film is from pre-heat roll 380, between draw nip roll 385 and draw advanced through corona treating Station at a rate of about roll 390, over draw roll 390, between draw nip roll 395 and 300 to about 600 feet per minute, and in one embodiment draw roll 400, over draw roll 400 to preheat roll 405. Draw about 345 feet per minute. roll 390 is operated at a temperature of about 160° F (71.1 0052 The hot-stretching and annealing of the film C.) to about 200° F (93.3° C), and in one embodiment at increases stiffness of the film in the machine direction but about 180° F (82.2°C.) The film is advanced over draw roll leaves the film relatively flexible in the cross direction. This 390 at a rate of about 40 to about 130 feet per minute, and process may be referred to as uniaxial Stretching. In one in one embodiment at about 89 feet per minute. Draw roll embodiment, it is contemplated to use unbalanced or bal 400 is operated at a temperature of about 170° F (76.7° C) anced biaxial Stretching of the film to achieve a Satisfactory to about 220 F. (104.4° C), and in one embodiment at about stiffness differential between the machine and cross direc 190° F (87.8° C.). The film is advanced over draw roll 400 tions, with the degrees of Stretching and Stiffness in the at a rate of about 300 to about 600 feet per minute, and in machine direction exceeding those in the croSS direction. one embodiment at about 402 feet per minute. The film Whether the stretching is biaxial or uniaxial, that is, whether advances from pre-heat roll 405 to pre-heat roll 410. Pre there is little (relatively) or no stretching in the cross heat roll 405 is operated at a temperature of about 190 F. direction, the degree of Stretching in the machine direction (87.8° C) to about 230° F (110° C), and in one embodiment exceeds that in the croSS direction So that the film is about 210° F (98.9°C.) Pre-heat roll 410 is operated at a Substantially Stiffened in the machine direction and remains temperature of about 210° F (98.9° C.) to about 250 F. relatively flexible in the cross direction. Therefore the film, (121.1° C), and in one embodiment about 230° F (110° C). whether uniaxially or biaxially stretched, may be referred to The film is advanced from pre-heat roll 410, between draw as having a machine direction Stiffness differential. nip roll 415 and draw roll 420, over draw roll 420, between 0053 Uniaxial hot-stretching and annealing are also draw nip roll 425 and draw roll 430, over draw roll 430 and important to the development of in-mold label film tensile then to guide roll 435. Draw roll 420 is operated at a properties necessary to withstand the mechanical and ther temperature of about 240° F (115.6° C) to about 280° F. mal Stresses of conventional printing techniques of the type (137.8° C), and in one embodiment at about 260° F (126.7 used in processing paper labels. C.). Draw roll 430 is operated at a temperature of about 230 0054 The inventive films are characterized by a machine F. (110° C) to about 270° F (132.2° C), and in one direction Shrinkage after hot-stretching and annealing of leSS embodiment at about 250° F (121.1° C.). The effect of than about 2%, and in one embodiment less than about 1.5%, advancing the film from draw roll 390 to draw roll 400 and and in one embodiment less than about 1%, and in one from draw roll 420 to draw roll 430 is to stretch the film embodiment less than about 0.75%, and in one embodiment sufficiently to provide the film with a machine direction in the range of about 0.1 to about 1%, and in one embodi orientation. The stretch ratio may range from about 5.0 to ment in the range of about 0.25 to about 0.75%. Shrinkage about 5.9, and in one embodiment at about 5.75. The film is then advanced from annealing roll 440 to annealing roll 450. is determined using test method ASTM D 2739-96. Annealing roll 440 is operated at a temperature of about 0055 As schematically illustrated in FIG. 3, the 250° F (121.1° C) to about 290° F (143.3° C), and in one stretched and annealed film 100, which may be supplied in embodiment at about 270° F (132.2° C). Annealing roll 450 the form of self-wound roll 560, may be printed or decorated is operated at a temperature of about 230 F. (110° C) to in a printing press 600 in which the film is subjected to about 270° F (132.2° C), and in one embodiment at about mechanical and thermal StreSS incident to the printing itself 250 F. (121.1° C.). The film is advanced over annealing and to the drying of the ink by exposure to heat as Such or rolls 440 and 450 at a rate of about 285 to about 400 feet per by exposure to ultraViolet radiation which tends to also minute, and in one embodiment at about 345 feet per minute. generate infrared radiation. Print indicia may be applied to The film is then advanced from annealing roll 450 to cooling skin layer 120. nip roll 460, between cooling nip roll 460 and cooling roll 0056. Following printing and drying, the film may be 470, over cooling roll 470 to cooling roll 480, over cooling sheeted and Stacked in a manner Similar to that known for roll 480 to guide roll 490, over guide roll 490 to guide roll the sheeting of paper-backed label Stock. Cutting is indicated 510. Cooling roll 470 is operated at a temperature of about 150° F (65.6° C) to about 250° F (121.1° C), and in one by arrow 610 in the drawings. The severed sheets 620 are embodiment at about 200° F (93.3°C.). Cooling roll 480 is stacked to form stack 630. The stack may contain, for operated at a temperature of about 140°F. (60° C) to about example, 100 or 200 sheets. For clarity of illustration, in the 200° F (93.3° C), and in one embodiment at about 160°F. drawing the thickness of the sheets is greatly exaggerated (71.1° C). The film is advanced over cooling rolls 470 and and the stack 630 is therefore shown as made up of only a 480 at a rate of about 300 to about 600 feet per minute, and relatively Small number of sheets. Each sheet in the Stack is in one embodiment about 345 feet per minute. The film is intended to provide material for several individual labels to advanced from guide roll 510 to guide roll 520, then over be die-cut from the sheeted material. In the particular guide roll 520 to corona treating station 540. The thickness example described, nine labels are die-cut from each sheet. of the film is monitored using film thickneSS measuring The sheets in the Stack are accurately registered with each device 530 which is positioned between guide roll 510 and other so that the labels to be cut from the sheet will be guide roll 520. In the corona treating station, both sides of formed in correct registration to the printing that appears on the film are treated to increase Surface energy. The Surface their face according to the pattern printed by the press 600. US 2004/0224175 A1 Nov. 11, 2004

0057) If the film is too limp, accurate stacking is pre 0062. At the site of container manufacture, stacks 660 of vented due to the inability to guidingly control positioning individual labels are loaded in dispensing magazine 670 as of a limp Sheet by means of belts, guideways, Stops or schematically illustrated in FIG.8. For example, the labels Similar guiding mechanisms (not shown) with any degree of may be advanced to the front of the magazine by a Spring accuracy. The stiffening of the inventive film by hot-stretch 680, and may be lightly retained for pick-off by mechani ing to desired Stiffnesses, as discussed above, allows for cally retracting retainer fingers 690. A robotic label feed accurate Stacking to be achieved. In one embodiment, the head 700 carries vacuum cups 710 adapted to be advanced bending stiffness in the machine direction (MD) is at least by a mechanism (not shown) internal to the head 700 to pick 100 nM, and in one embodiment at least about 150 nM. The off the front label 660a in the stack 660. The vacuum cups croSS direction bending Stiffness in one embodiment is at are retracted for translating movement of the head and the least 50 nM, and in one embodiment at least 70 nM. single picked-off label 660a into the opened mold 720. 0.058 Accurate stacking and Subsequent handling of the Movement of the head 700 is actuated by translating cylin sheets or labels formed therefrom is also impeded if static der 730. The vacuum cups 710 are advanced again to apply charges are present on the Sheets or labels. The antistatic the picked-off label 660a to the interior surface of the mold additives discussed above act to remove or dissipate Static and release it. The label may then be held accurately in charges. position within the mold by vacuum applied to the mold wall through vacuum lines 740 while the label feed head 700 is 0059 Individual labels are formed in a known manner by retracted. The vacuum line outlets to the interior of the mold hollow punches or cutting dies 640 carried on a head 650, may be flush with the interior surface of the mold, as shown, seen in bottom plan view in FIG. 4 and in side elevation in So that the label occupies part of the mold cavity proper. In FIGS. 5 and 6. The cutting dies punch out the labels from other words, there is no receSS on the interior mold Surface the Stack 630, producing in each cutting cycle a number of to accommodate the label. Stacks 660 of individual labels shown in FIG. 7. In the particular example described, nine Stacks of individual 0063 A hot workpiece or parison (not shown) of high labels are produced in each cutting cycle. density polyethylene or Similar thermoplastic resin is fed 0060 Alternatively, following printing and drying, the into the mold 720, the mold is closed, and the parison is Stock may be fed into a rotary Steel die (not shown) at the expanded in a known manner to complete the formation of end of the printing press line and cut into labels. AS the cut the molded container. The hot-Stretching and annealing labels and Surrounding matrix of waste material exit from temperatures used in making the inventive film exceed the the rotary Steel die, the matrix is pulled away at an angle Service temperature in the mold. To assure a uniform joining from the labels which are sufficiently stiff to continue their of the label to the container, it is desirable that the softening forward travel into a nip of a pair of feed belts (not shown) temperature of the in-mold label film be close to the service for collection into stacks 660. Thus, the machine direction temperature. If the label is on, not in, the interior Surface of StiffneSS is utilized in a direct label cutting and Separating the mold, the label becomes embedded in the workpiece to proceSS which eliminates the cutting Step at 610 as well as which it is adhered, thus advantageously providing an inset the other steps described with respect to FIGS. 4, 5 and 6. label that is flush with the container Surface and that replaces and therefore Saves a portion of the charge for the molded 0061 The stacks 660 of individual labels are stabilized Workpiece or container without diminishing the Structural by Suitable wrapping or packaging (not shown) in a manner integrity of the workpiece to any detected degree. similar to that previously used with paper-backed labels. The stabilized stacks 660 are then moved or transported to the EXAMPLES Site where the blow-molded, injection molded or injection blown containers are being manufactured, which often is at 0064. The following examples are provided to further a different place than the Site of label manufacture. disclose the invention. The ingredients used are listed below.

TABLE 1.

Trade Name Description Ampacet 101087 70% loaded CaCOs in EMA (3 micron particles) Ampacet 101501 Non-migratory slip (10% active) Ampacet 101710 Non-migratory anti-stat agent (50% active) Ampacet 110069 70% loaded TiO, in LLDPE (rutile) Ampacet 400880 Anti-block (3% loaded) Seablock-4 (5 micron particles) DuPont Bynel E418 Anhydride modified EVA (0.95 g/cc density, 165 F. Mp) Escorene PD7623.E.1 Medium-impact copolymer polypropylene Exact 4151 Metallocene LLDPE (plastomer) 2.2 MI, 192 F. Mp, 0.895 g/cc density Exxcelor PA609A Hydrogenated polyterpene Exact 0210 Metallocene LLDPE (plastomer) 10 MI, 205 F. Mp, 0.902 g/cc density Exact 0230 Metallocene LLDPE (plastomer) 30 MI, 203 F. Mp, 0.902 g/cc density Exact 82O3 Metallocene LLDPE (plastomer) 3 MI, 205 F. Mp, 0.882 g/cc density Exact 8210 Metallocene LLDPE (plastomer) 10 MI, 165 F. Mp, 0.882 g/cc density Affinity PT 1450 Metallocene LLDPE (plastomer) 7.5 MI, 208 F. Mp, 0.902 g/cc density Huntsman P4G4K-038 Homopolymer polypropylene, nucleated, clarified (12 MFR) Huntsman P4CSK-123A Homopolymer polypropylene, nucleated, clarified with anti-stat (20 MFR) Ticona Topas 8007-D61 Cyclic olefin copolymer

US 2004/0224175 A1 Nov. 11, 2004

0068 The bending stiffness of films of Examples 1-6 8. The film of claim 1 wherein the core layer further were measured with a Lorentzen & Wettre Bending Resis comprises a cyclic olefin copolymer. tance Tester. The Bending Resistance Tester measures the 9. The film of claim 1 wherein the thickness of the core force necessary to deflect a rectangular test piece, clamped layer is about 40% to about 80% of the overall thickness of at one end, through a specified bending angle when the force the multilayer film. is applied near to the free end of the test piece (ISO 2493). 10. The film of claim 1 wherein the thickness of the heat The Stiffness in the machine direction and the croSS direction activatable layer is about 10% to about 25% of the overall for each film is given in Table 4. The stiffness given is thickness of the multilayer film. normalized at a film thickness of 4.5 mil. 11. The film of claim 1 wherein the thickness of the heat activatable layer is about 20% of the overall thickness of the TABLE 4 multilayer film. 12. The film of claim 1 wherein the blend of polypropy Example MD Stiffness (mN) CD Stiffness (mN) lene homopolymer and polyterpene comprises about 50% to 1. 1819 97.1 about 80% by weight of polypropylene homopolymer and 2 164.O 78.2 about 20% to about 50% by weight of polyterpene, based on 3 1291 6O.O the weight of the polypropylene homopolymer and polyter 4 127.4 52.3 5 153.4 71.5 pene. 6 198.7 91.2 13. The film of claim 1 wherein the core layer further comprises a metallocene catalyzed polyolefin resin. 14. The film of claim 1 wherein the core layer further 0069. While the invention has been explained in relation comprises a pigment. to specific embodiments, it is to be understood that various 15. The film of claim 1 wherein the skin layer comprises modifications thereof will become apparent to those skilled a blend of a polypropylene homopolymer and a filler mate in the art upon reading the Specification. Therefore, it is to rial. be understood that the invention disclosed herein is intended 16. The film of claim 15 wherein the skin layer further to cover Such modifications as fall within the Scope of the comprises a metallocene catalyzed polyethylene. appended claims. 17. The film of claim 15 wherein the filler material comprises calcium carbonate 1. A multilayer film for use in making an in-mold label, 18. The film of claim 15 wherein the polyethylene has a comprising: density in the range of about 0.860 and 0.920 g/cm. a core layer having an upper Surface and a lower Surface; 19. The film of claim 15 wherein the polypropylene homopolymer has a melt flow rate of at least 8 g/10 min. a skin layer overlying the upper Surface of the core layer; 20. The film of claim 1 wherein the tie layer comprises a a heat activatable layer bonded to the lower surface of the polypropylene homopolymer and a metallocene catalyzed core layer by a tie layer; polyethylene resin. 21. The film of claim 1 wherein the heat activatable layer wherein the core layer comprises a blend of a propylene comprises a metallocene catalyzed polyethylene resin. homopolymer and at least one polyterpene and wherein 22. The film of claim 21 further comprising an antiblock the multilayer film is oriented in the machine direction additive. only and heat Set. 23. The film of claim 21 further comprising a non 2. The film of claim 1 wherein the polypropylene migratory slip agent. homopolymer has a melt flow rate of at least about 8 g/10 24. The film of claim 21 further comprising a non . migratory antistatic additive. 3. The film of claim 1 wherein the polypropylene 25. The film of claim 1 wherein the bending stiffness of homopolymer has a melt flow rate of at least about 10 g/10 the film in the machine direction is at least 100 nM. . 26. The film of claim 1 wherein the bending stiffness of 4. The film of claim 1 wherein the polypropylene the film in the machine direction is at least 150 nM. homopolymer has a melt flow rate of about 20 g/10 min. 27. The film of claim 1 wherein the bending stiffness of 5. The film of claim 1 wherein the polypropylene the film in the cross direction is at least 50 nM. homopolymer comprises a nucleated polypropylene. 28. The film of claim 1 wherein the bending stiffness of 6. The film of claim 1 wherein the polyterpene resin is a the film in the cross direction is at least 70 nM. hydrogenated polyterpene having a melt index of about 8 to 29. The film of claim 1 wherein print indicia is applied to about 15 g/10 min. the skin layer. 7. The film of claim 1 wherein the core layer further comprises a medium impact copolymer polypropylene.